Evaluation of the effect of texture size and rounding process on 3-dimensional flexibility of c-Si wafer

Vehicles are expected to be a new application field for solar cells. Since vehicle bodies have complicated three-dimensional curved surfaces designed to improve aerodynamic performance, there is a need for flexible solar cells that can be installed on such surfaces. To this end, research has focused on single-crystalline Si solar cells with high conversion efficiency and reliability, since the flexibility of Si wafers improves as they become thinner. Previous studies have reported that the texture structure to improve the light absorption on the Si wafer surface affects the three-dimensional flexibility. In this work, we perform a Ball-on-Ring test to determine how texture size and rounding treatment affect the flexibility of c-Si wafers and measure the flexibility. The results demonstrate that the rounding process increases flexibility, while the texture size reduction improves flexibility.